1. Field of the Invention
The present invention relates to a storage device employing a replaceable storage medium. More particularly, this invention is concerned with a storage device, having a loading mechanism, such as an optical disk drive employing a replaceable optical disk cartridge that looks like a cartridge and has a magneto-optical disk stowed in the cartridge.
2. Description of the Related Art
In recent years, the processing ability and processing speed of personal computers have improved, and the capacities of operating systems and application software packages for programs or data have expanded. Under these circumstances, storage devices must be compact and low-cost. Moreover, there is an increasing demand for a storage device offering a large storage capacity and a high processing speed.
An optical disk drive has begun to prevail as a storage device capable of meeting the demands for a compact design, a low cost, a large storage capacity, and a high processing speed. An optical disk cartridge having an optical disk stowed in a cartridge is available as an optical disk employed in such an optical disk drive. Along with the prevalence of the optical disk drive employing the optical disk cartridge, there arises a demand for resistivity to rough handling, stable performance, improved reliability, and reduction in the cost.
The stability of an optical disk cartridge loaded on a base of an optical disk drive after being inserted into the optical disk drive may be impaired if the cartridge is handled roughly. Mechanisms included in the optical disk drive are required to work properly when the optical disk cartridge is inserted in the optical disk drive. Moreover, the mechanisms are required to be inexpensive.
In the optical disk drive employing the optical disk cartridge, an object lens included in an optical system and an optical disk, that is a storage medium, must run precisely parallel to each other for the purpose of attaining a high density of the data stored in an optical disk. As a solution, a tilt follow-up mechanism may be included in an optical pickup included in the optical system.
The solution of including the tilt follow-up mechanism in the optical pickup included in the optical system has disadvantages that the number of elements constituting the optical pickup increases, and the cost of an optical disk drive increases accordingly, and the number of components that must be controlled increases. These disadvantages become an obstacle to realization of an inexpensive optical disk drive.
Another solution is that a mechanism is included for adjusting the tilts of an object lens and the optical disk during assembling of optical elements constituting an optical system for the purpose of readily attaining parallelism between the object lens included in the optical system and the optical disk. An optical disk drive adopting the solution has been put into practical use. To realize the tilt adjusting mechanism, an actuator including a tilt adjusting mechanism is generally adopted for the optical pickup.
In particular, a typical optical pickup is composed of a carriage movable in a radial direction of an optical disk and an inching actuator capable of inching for tracking or focusing while being mounted on the carriage. Another type of optical pickup is such that the body of a carriage controls the inching in the radial direction (direction of tracks) on an optical disk and an inching actuator mounted on the carriage controls focusing.
However, the type of optical pickup composed of the carriage movable in the radial direction on an optical disk and the inching actuator capable of inching for tracking or focusing while being mounted on the carriage has disadvantages. Specifically, the number of optical elements is so large that part costs and machining costs are high. Therefore, this type of optical pickup is not favorable from the viewpoint of reducing the cost of the optical disk drive.
The type of optical pickup in which the body of the carriage controls inching in the radial direction on an optical disk and the actuator mounted on the carriage controls focusing alone helps reduce the cost of an optical disk drive and allows compact design an optical disk drive. However, when the actuator is provided with a tilt adjusting mechanism, a tilt adjustment space is needed. This poses a problem in that the height of the optical disk drive increases. Furthermore, for constructing a high-performance optical disk drive, the actuator and a magnetic circuit for generating a driving force for the actuator must be tilted. This discourages efforts to design a compact optical disk drive.